one of known methods for measuring, forecasting and managing risk is value at risk, which recently has been used by financial institutions extensively. value at risk (var) is a method for recognizing and evaluating risk and uses standard statistical techniques that have daily using in other contexts. this research is seeking a career for managing investment risk in stock exchange and selection ...

in this study, monte carlo statistical mechanical simulations for vinblastine and vincristine werecarried out in standard manner using the metropolis sampling technique in canonical (t, v, n)ensemble., geometrical optimizations of vinblastine and vincristine were carried out with the hfmethod coupled to 6-31g(d) basis sets for all atoms. simulation was done by four force fields ofmm+, bio+, amb...

an important need in radiation therapy is a fast and accurate treatment planning system. this system using ct data and characteristics of the radiation beam, calculates the dose in all points of the patient’s volume. two main factors in planning system are “accuracy” and “speed”. according to these factors, various generation of treatment planning systems are developed.   this article is the re...

background: the monte carlo method is the most accurate method for simulation of radiation therapy equipment. the linear accelerators are currently the most widely used machines in radiation therapy centers. methods: in this work, a monte carlo modelling of the siemens oncor linear accelerator in 6 mv and 18 mv beams was performed. the results of simulation were validated by measurements in wat...

Background: Monte Carlo and experimental relative dose determination in a water phantom, due to a high dose rate (HDR) 192Ir source is presented for real energy spectrum and monochromatic at 356 keV. Materials and Methods: The dose distribution has been calculated around the 192Ir located in the center of 30 cm ×30 cm ×30 cm water phantom using MCNP4C code by Monte Carlo method. Relati...

Background: Iodine brachytherapy sources with low photon energies have been widely used in treating cancerous tumors. Dosimetric parameters of brachytherapy sources should be determined according to AAPM TG-43U1 recommendations before clinical use. Monte Carlo codes are reliable tools in calculation of these parameters for brachytherapy sources. Materials and Methods: Dosimetric param...

background: because of the adverse effects of ionizing radiation on fetuses, prior to radiotherapy of pregnant patients, fetal dose should be estimated. fetal dose has been studied by several authors in different depths in phantoms with various abdomen thicknesses (at). in this study, the effect of maternal at and depth in fetal dosimetry was investigated, using peripheral dose (pd) distributio...

introduction: the key characteristics of positron emission tomography (pet) are its quantitative capability and its sensitivity, which allow the in vivo imaging of biochemical interactions with small amounts of tracer concentrations. therefore, accurate quantification is important. however, it can be sensitive to several physical factors. the aim of this investigation is the assessment of the e...